Commit 33bdedce authored by Namhyung Kim's avatar Namhyung Kim Committed by Arnaldo Carvalho de Melo
Browse files

perf tools: Protect dso cache fd with a mutex 



When dso cache is accessed in multi-thread environment, it's possible to
close other dso->data.fd during operation due to open file limit.
Protect the file descriptors using a separate mutex.

Signed-off-by: default avatarNamhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1431909055-21442-28-git-send-email-namhyung@kernel.org


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 8e67b725

tools/perf/util/dso.c

+72 −26
Original line number Diff line number Diff line
@@ -265,6 +265,7 @@ int __kmod_path__parse(struct kmod_path *m, const char *path, 
 */

static LIST_HEAD(dso__data_open);

static long dso__data_open_cnt;

static pthread_mutex_t dso__data_open_lock = PTHREAD_MUTEX_INITIALIZER;



static void dso__list_add(struct dso *dso)

{
@@ -434,7 +435,9 @@ static void check_data_close(void) 
 */

void dso__data_close(struct dso *dso)

{

	pthread_mutex_lock(&dso__data_open_lock);

	close_dso(dso);

	pthread_mutex_unlock(&dso__data_open_lock);

}



/**
@@ -457,6 +460,8 @@ int dso__data_fd(struct dso *dso, struct machine *machine) 
	if (dso->data.status == DSO_DATA_STATUS_ERROR)

		return -1;



	pthread_mutex_lock(&dso__data_open_lock);



	if (dso->data.fd >= 0)

		goto out;
@@ -479,6 +484,7 @@ out: 
	else

		dso->data.status = DSO_DATA_STATUS_ERROR;



	pthread_mutex_unlock(&dso__data_open_lock);

	return dso->data.fd;

}
@@ -583,7 +589,8 @@ dso_cache__memcpy(struct dso_cache *cache, u64 offset, 
}



static ssize_t

dso_cache__read(struct dso *dso, u64 offset, u8 *data, ssize_t size)

dso_cache__read(struct dso *dso, struct machine *machine,

		u64 offset, u8 *data, ssize_t size)

{

	struct dso_cache *cache;

	struct dso_cache *old;
@@ -592,11 +599,24 @@ dso_cache__read(struct dso *dso, u64 offset, u8 *data, ssize_t size) 
	do {

		u64 cache_offset;



		ret = -ENOMEM;



		cache = zalloc(sizeof(*cache) + DSO__DATA_CACHE_SIZE);

		if (!cache)

			return -ENOMEM;



		pthread_mutex_lock(&dso__data_open_lock);



		/*

		 * dso->data.fd might be closed if other thread opened another

		 * file (dso) due to open file limit (RLIMIT_NOFILE).

		 */

		if (dso->data.fd < 0) {

			dso->data.fd = open_dso(dso, machine);

			if (dso->data.fd < 0) {

				ret = -errno;

				dso->data.status = DSO_DATA_STATUS_ERROR;

				break;

			}

		}



		cache_offset = offset & DSO__DATA_CACHE_MASK;
@@ -606,6 +626,11 @@ dso_cache__read(struct dso *dso, u64 offset, u8 *data, ssize_t size) 


		cache->offset = cache_offset;

		cache->size   = ret;

	} while (0);



	pthread_mutex_unlock(&dso__data_open_lock);



	if (ret > 0) {

		old = dso_cache__insert(dso, cache);

		if (old) {

			/* we lose the race */
@@ -614,8 +639,7 @@ dso_cache__read(struct dso *dso, u64 offset, u8 *data, ssize_t size) 
		}



		ret = dso_cache__memcpy(cache, offset, data, size);



	} while (0);

	}



	if (ret <= 0)

		free(cache);
@@ -623,8 +647,8 @@ dso_cache__read(struct dso *dso, u64 offset, u8 *data, ssize_t size) 
	return ret;

}



static ssize_t dso_cache_read(struct dso *dso, u64 offset,

			      u8 *data, ssize_t size)

static ssize_t dso_cache_read(struct dso *dso, struct machine *machine,

			      u64 offset, u8 *data, ssize_t size)

{

	struct dso_cache *cache;
@@ -632,7 +656,7 @@ static ssize_t dso_cache_read(struct dso *dso, u64 offset, 
	if (cache)

		return dso_cache__memcpy(cache, offset, data, size);

	else

		return dso_cache__read(dso, offset, data, size);

		return dso_cache__read(dso, machine, offset, data, size);

}



/*
@@ -640,7 +664,8 @@ static ssize_t dso_cache_read(struct dso *dso, u64 offset, 
 * in the rb_tree. Any read to already cached data is served

 * by cached data.

 */

static ssize_t cached_read(struct dso *dso, u64 offset, u8 *data, ssize_t size)

static ssize_t cached_read(struct dso *dso, struct machine *machine,

			   u64 offset, u8 *data, ssize_t size)

{

	ssize_t r = 0;

	u8 *p = data;
@@ -648,7 +673,7 @@ static ssize_t cached_read(struct dso *dso, u64 offset, u8 *data, ssize_t size) 
	do {

		ssize_t ret;



		ret = dso_cache_read(dso, offset, p, size);

		ret = dso_cache_read(dso, machine, offset, p, size);

		if (ret < 0)

			return ret;
@@ -668,21 +693,42 @@ static ssize_t cached_read(struct dso *dso, u64 offset, u8 *data, ssize_t size) 
	return r;

}



static int data_file_size(struct dso *dso)

static int data_file_size(struct dso *dso, struct machine *machine)

{

	int ret = 0;

	struct stat st;

	char sbuf[STRERR_BUFSIZE];



	if (!dso->data.file_size) {

		if (fstat(dso->data.fd, &st)) {

			pr_err("dso mmap failed, fstat: %s\n",

	if (dso->data.file_size)

		return 0;



	pthread_mutex_lock(&dso__data_open_lock);



	/*

	 * dso->data.fd might be closed if other thread opened another

	 * file (dso) due to open file limit (RLIMIT_NOFILE).

	 */

	if (dso->data.fd < 0) {

		dso->data.fd = open_dso(dso, machine);

		if (dso->data.fd < 0) {

			ret = -errno;

			dso->data.status = DSO_DATA_STATUS_ERROR;

			goto out;

		}

	}



	if (fstat(dso->data.fd, &st) < 0) {

		ret = -errno;

		pr_err("dso cache fstat failed: %s\n",

		       strerror_r(errno, sbuf, sizeof(sbuf)));

			return -1;

		dso->data.status = DSO_DATA_STATUS_ERROR;

		goto out;

	}

	dso->data.file_size = st.st_size;

	}



	return 0;

out:

	pthread_mutex_unlock(&dso__data_open_lock);

	return ret;

}



/**
@@ -700,17 +746,17 @@ off_t dso__data_size(struct dso *dso, struct machine *machine) 
	if (fd < 0)

		return fd;



	if (data_file_size(dso))

	if (data_file_size(dso, machine))

		return -1;



	/* For now just estimate dso data size is close to file size */

	return dso->data.file_size;

}



static ssize_t data_read_offset(struct dso *dso, u64 offset,

				u8 *data, ssize_t size)

static ssize_t data_read_offset(struct dso *dso, struct machine *machine,

				u64 offset, u8 *data, ssize_t size)

{

	if (data_file_size(dso))

	if (data_file_size(dso, machine))

		return -1;



	/* Check the offset sanity. */
@@ -720,7 +766,7 @@ static ssize_t data_read_offset(struct dso *dso, u64 offset, 
	if (offset + size < offset)

		return -1;



	return cached_read(dso, offset, data, size);

	return cached_read(dso, machine, offset, data, size);

}



/**
@@ -737,10 +783,10 @@ static ssize_t data_read_offset(struct dso *dso, u64 offset, 
ssize_t dso__data_read_offset(struct dso *dso, struct machine *machine,

			      u64 offset, u8 *data, ssize_t size)

{

	if (dso__data_fd(dso, machine) < 0)

	if (dso->data.status == DSO_DATA_STATUS_ERROR)

		return -1;



	return data_read_offset(dso, offset, data, size);

	return data_read_offset(dso, machine, offset, data, size);

}



/**

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